The Diablo has had more support in the past, but the T-Rex is slightly quicker at changing channels.
You will need a Cas 3 programmer for the Diablo Cam, and either a Cas 3 or a card programmer, capable of programming a Fun Card 7, or in programming on Phoenix mode, to program the T-Rex loader card.
With changes in encryption imminent, particularly for Premiere, maybe a cheap patchable receiver might be a better purchase or wait a little while.
What equipment do you currently have and what satellites can you receive?